Bang, Rattle, Click: Scary Furnace Sounds & What They Mean

GET STARTED NOW
Available 24/7 - No Overtime Charges, EVER!

Bang, Rattle, Click: Scary Furnace Sounds & What They Mean

From creepy crawlies to exploding furnaces, basements, along with their furnaces and boilers, are a common trope used in horror stories. And for good reason!

Nobody enjoys a dark descent into the basement, especially if there are scary sounds coming from the furnace. While some point to the attic or the shed as the scariest place in the home, most would probably agree that the basement has a certain supernatural je ne se qua.

While we can’t speak on the ghostly aspect, we can tell you where all those creepy sounds are coming from. While some noises are harmless, others can indicate a significant danger.

Scary Furnace Sounds

 

BOOM!

A loud boom or bang sound coming from your furnace usually means a delayed ignition and should be checked out by a professional as soon as possible. This small gas explosion is the result of gas building up in your furnace chamber due to the burner not lighting properly, similar to what you may have experienced with a gas grill.

Why does your furnace have a delayed ignition? There are a couple of reasons:

  • a high air-to-gas ratio making it difficult to light
  • not enough gas probably due to low gas pressure
  • your burners are clogged with debris, worn down, or otherwise compromised

If you are having ignition problems, it is important to schedule professional furnace maintenance as soon as you can to have it cleaned and inspected. Turn off your furnace from the source and wait for a qualified HVAC professional to deem it safe to turn it back on.

House-Shaking Rumble

If you hear a loud house-shaking rumbling throughout your house when the furnace completes one of its heating cycles, this is most likely due to oil that continues to burn in your combustion chamber after the burners shut off. Rumbling can also indicate a problem with your burners, flame sensor, and pilot light.

It is important to schedule professional furnace maintenance if this happens, as you could be releasing dangerous carbon monoxide gases into your home. Click here to read about a true-life carbon monoxide horror story and what you can do to prevent and detect CO leaks in your home.

Loud Rattle or Bang

If you hear a bang or loud rattling as your furnace kicks on, this is another indication of a carbon monoxide problem. A bang or rattling sound from your furnace could mean that you have a cracked heat exchanger, which is the biggest cause of carbon monoxide leaks.

A rattling sound before the blower comes on almost always means a cracked heat exchanger. Call your heating and cooling professional as soon as you can to fix this problem, which could turn deadly if ignored!

If you are hearing rattling while your furnace is on, however, it’s most likely because of loose connections in your duct system. You could try to fix this by DIY sealing your ductwork or you could call a professional to fix and seal your entire duct system. The rattling could also be coming from loose panels that need to be tightened.

Scraping and Rattling Metal

If you are hearing metal against metal, there’s probably something wrong with your blower wheel. This could be due to a number of reasons:

  • the blower wheel has become loose and is now hitting the side of its housing.
  • a piece in your heating system has come loose and is stuck in the blower wheel.
  • the motor or blower wheel is broken and needs to be repaired or replaced.

As soon as you hear this noise, turn off the furnace immediately and call a professional to troubleshoot and fix the situation. If you ignore this metal clanging noise, you could break your blower and other important components of you furnace system.

Squealing and Grinding

Squealing, screeching, and grinding noises are often the result of something amiss with your blower. Either the blower belt has loosened or slipped off its track or your motor bearings are failing and need to be replaced or oiled by a professional. While not the most dangerous sound you can hear from your furnace, it’s one that you should have fixed as soon as possible to avoid more serious repairs.

Clicking Noises

A clicking noise is normal when you furnace is first turning on. This is the sound of your ignition clicking on. If you furnace starts to click, the blower turns on, and then back off again, you could have a problem with your flame sensor. Call a professional to have your flame sensor checked and cleaned.

If your furnace continues to click without ever turning on, you may have loose wiring or a leaking gas valve.

Buzzing

A buzzing noise coming from your furnace is usually the result of something loose in your furnace’s transformer. Over time, screws and other parts in your transformer can become loose and create a buzzing sound. Call a professional HVAC technician to clean and tighten your furnace parts.

Whistling

A whistling sound may be the result of a clogged or dirty air filter. Restricted airflow to your furnace can cause a whistling sound. Remember to change your furnace filter every 1-3 months to increase airflow, improve indoor air quality, and stop that whistling sound!

Annual Furnace Maintenance

Annual HVAC maintenance on your furnace in the fall and your air conditioning in the spring prevents most of these problems from forming in the first place, such as dirty, clogged burners. When you schedule heating and/or cooling maintenance with Interstate Heating and Air Conditioning, you will receive a very thorough diagnosis of your heating, ventilation, and air conditioning systems.

Click here to read our professional heating and cooling maintenance checklist and what you can do to supplement professional efforts.

For more information on gas furnace safety and maintenance tips, read our other blog articles on the topic:


If you have any questions about your furnace sounds is making, don’t hesitate to give us a call at 405-794-8900. We want you to be comfortable, safe, and save on your heating bills this winter!

An important component of saving money on your utility bills is scheduling annual maintenance with your HVAC professional. To schedule your fall furnace tune-up, we’d love to assist you. You can schedule service with Interstate Heating and Air Conditioning online or give us a call: 405-794-8900.

Stay connected with us on Facebook, Twitter, and Google+ for more useful HVAC information and advice!

Sign up for our Maintenance Plan for FREE tune-ups and 20% discount on all repairs!

We look forward to serving you!

[sgmb id=1]
By |2018-04-05T18:29:05+00:00November 1st, 2015|Blog|0 Comments

Call Us Today! 405-912-5900

Let's get going

All of our technicians go through a rigorous application and training program. You can remain confident that our trusted technicians will treat you and your home with care and respect. We wear shoe covers and make sure that we leave your home as clean as we found it, or better.